Constructing electric motors in a manner that facilitates their assembly, and devising lower cost methods of assembling such motors, have received much attention over many years.
It has been proposed for various reasons to construct the laminated stator core from at least two core parts which are assembled together, as disclosed in U.S. Pat. Nos. 4,071,787; 3,436,574; 3,365,687; 3,443,137; 3,054,027; 2,330,824; 3,014,140; 2,294,322; and 2,982,873.
In U.S. Pat. No. 3,436,574 the laminated core has a substantially rectangular shape in cross-section with poles, which partially surround a rotatably supported armature, extending into a central opening from two opposite sides of the laminated core. The rotational axis of the armature, as is usual, forms the longitudinal axis of the stator. The core is formed by a U-shaped core part, which includes the inwardly extending poles, and a yoke which is fastened across the free ends of the arms of the U-shaped core part. A field winding encircles the yoke. Due to the inwardly extending poles, the arcuate inner surfaces of which closely surround the armature, the armature must be assembled axially into and through the central space between the poles by movement along the longitudinal axis of the stator.
Similarly, in the case of other stators, the armature is assembled into the stator assembly axially by movement along the longitudinal axis of the stator.
In assembling electric motors generally it should be noted that assembly movements take place along several different directions.